Dynamic Form

DynamicFormPhase1.kt

import android.content.Context
import android.view.View
import android.widget.LinearLayout
import io.reactivex.Observable

interface Input {

    val mandatory : Boolean
    val focusIds : Array<Int>
    fun buildView(context : Context) : View
    val completeSignal : Observable<Boolean>
    val layoutParams : LinearLayout.LayoutParams

}

class InputForeman(private val schema : List<Input>) {
    
    fun build(context: Context) : LinearLayout {
      TODO("buildView into vertical LinearLayout based on it's layoutParams")
    }
  
    fun observeCompletion() : Observable<Boolean> {
        TODO("join all schema completeSignal") 
    }

}

DynamicFormPhase2.kt

import android.content.Context
import android.view.View
import android.widget.LinearLayout
import io.reactivex.Observable

interface Input {

    val mandatory : Boolean
    fun buildView(context : Context) : View
    val completeSignal : Observable<Boolean>
    val layoutParams : LinearLayout.LayoutParams

}

/**
 * Then I realize that every [Input] needs id so you can set value to it
 */
typealias ID = String
class InputForeman(private val schema : Map<ID, Input>) {
    
    private lateinit var inputViews : Map<ID, View>

    fun build(context: Context) : LinearLayout {
        TODO("buildView into vertical LinearLayout based on it's layoutParams")
    }

    fun observeCompletion() : Observable<Boolean> {
        TODO("join all input completeSignal")
    }
    
    fun getValue() : Map<ID, Any?> {
        TODO("")
    }
    
    fun setValue(values : Map<ID, Any?>){
        TODO("")
    }

}

/**
 *
 * But this is still bad since it turns out, every implementation of [Input] i made, also made schema holds [View] instance unintentionally
 *
 * @sample
 *
 * class EditInput(override mandatory : Boolean) : Input {
 *
 *   private lateinit var editText : EditText
 *
 *   override fun buildView(context : Context) : EditText {
 *       editText = EditText(context)
 *       return editText
 *   }
 *
 *   override val completeSignal : Observable<Boolean>
 *       get() {
 *          return Observable.create { emit ->
 *              if(mandatory){
 *                  it.onNext(true)
 *                  editText.addOnTextChanged {
 *                      emit.onNext(it.toString().isNotEmpty())
 *                  }
 *              }else{
 *                  it.onNext(true)
 *              }
 *          }
 *       }
 *
 *   override val layoutParams = LinearLayout.LayoutParams(-1, -2)
 *
 * }
 * 
 * So, i can't do this, [Input] is better if it is immutable, so that i can save schema to storage
 */

DynamicFormPhase3.kt

import android.content.Context
import android.view.View
import android.widget.LinearLayout
import io.reactivex.Observable

interface Input {

    val mandatory : Boolean
    fun buildView(context : Context) : InputHolder
    val layoutParams : LinearLayout.LayoutParams

}

/**
 *  Now this is better
 */
class InputHolder(
    val view : View,
    val completeSignal : Observable<Boolean>,
    /**
     *  imagine if i have Composite Input where it buildView based on it's child input
     *  and imagine if this Composite Input somehow compose all EditText in horizontal manner
     *
     *
     *  Turns out i need view focusesId too. you can use [View.generateViewId] when you build the view
     */
    val focusedIds : Array<Int>
)

typealias ID = String
class InputForeman(private val schema : Map<ID, Input>) {

    private lateinit var inputHolders : Map<ID, InputHolder>

    fun build(context: Context) : LinearLayout {
        TODO("buildView into vertical LinearLayout based on it's layoutParams")
    }

    fun observeCompletion() : Observable<Boolean> {
        TODO("join all input completeSignal")
    }


    /**
     *  Turns out by making value [Any] is something you should not do.
     *  since you will lose the benefit of knowing what type the input value should be cast with
     */
    fun getValue() : Map<ID, Any?> {
        TODO("")
    }

    fun setValue(values : Map<ID, Any?>){
        TODO("")
    }


}

DynamicFormPhase4.kt

import android.content.Context
import android.view.View
import android.widget.LinearLayout
import io.reactivex.Observable


/**
 *  i want to made Input<T> with generic T so i can enforce the value for InputHolder
 *  is it good ? hmm.. i dunno.. if you do this. you might have need class<T> TOO!!
 *
 *  but let's try it..
 */
interface Input<T> {

    val cls : Class<T>
    val mandatory : Boolean
    fun buildView(context : Context) : InputHolder<T>
    val layoutParams : LinearLayout.LayoutParams

}

abstract class InputHolder<T>(
    val view : View,
    val completeSignal : Observable<Boolean>,
    val focusedIds : Array<Int>
){
    abstract fun setValue(value : T)
    abstract fun getValue() : T
}

/**
 *  But this is BAD TOO!!
 *
 *  T will be an invariant!!
 */

typealias ID = String
class InputForeman(private val schema : Map<ID, Input<*>>) {

    private lateinit var inputHolders : Map<ID, InputHolder<*>>

    fun build(context: Context) : LinearLayout {
        TODO("buildView into vertical LinearLayout based on it's layoutParams")
    }

    fun observeCompletion() : Observable<Boolean> {
        TODO("join all input completeSignal")
    }

    fun getValue() : Map<ID, Any?> {
        TODO("")
    }

    fun setValue(values : Map<ID, Any?>){
        TODO("")
    }

}

DynamicFormPhase5.kt

import android.content.Context
import android.view.View
import android.widget.LinearLayout
import io.reactivex.Observable


/**
 *  Enter my inspiration, JsonWriter and JsonReader
 */

typealias ID = String
interface Input<T> {

    /**
     * But writer and reader needs ID!!
     */
    val id : ID
    val cls : Class<T>
    val mandatory : Boolean
    fun buildView(context : Context) : InputHolder<T>
    val layoutParams : LinearLayout.LayoutParams

}

class Writer(){

    private val innerMap = mutableMapOf<ID, Any?>()
    
    val map : Map<ID, Any?> get() = innerMap
    
    fun <T> write(input : Input<T>, value : T){
        innerMap[input.id] = input.cls.cast(value)
    }

}

class Reader(private val map : Map<ID, Any?>){
 
    fun <T> read(input : Input<T>) : T?{
        val value = map.getValue(input.id)
        return input.cls.cast(value)
    }
}


abstract class InputHolder<T>(
    /**
     *  Turns out you need input from input holder
     */
    val input : Input<T>,
    val view : View,
    val completeSignal : Observable<Boolean>,
    val focusedIds : Array<Int>
){
    abstract fun write(writer: Writer)
    abstract fun read(reader: Reader)
}

class InputForeman(private val schema : List<Input<*>>) {

    private lateinit var inputHolders : Map<ID, InputHolder<*>>

    fun build(context: Context) : LinearLayout {
        TODO("buildView into vertical LinearLayout based on it's layoutParams")
    }

    fun observeCompletion() : Observable<Boolean> {
        TODO("join all input completeSignal")
    }


    /**
     *  Turns out this is different than you think,
     *  [InputHolder.write] is used to get value from view
     *  and [InputHolder.read] is used to set value from Values Map
     */
    fun getValue() : Map<ID, Any?> {
        val writer = Writer()
        for((id, inputHolder) in inputHolders){
            inputHolder.write(writer)
        }
        return writer.map
    }

    fun setValue(values : Map<ID, Any?>){
        val reader = Reader(values)
        for((id, inputHolder) in inputHolders){
            inputHolder.read(reader)
        }
    }

}

/**
 *  Another idea i have tried is making T a subclass of Value object to made it easier
 *  to be converted to moshi
 *
 *  To make it more complicated sometimes,
 *  sometimes you need [LiveData] object so that you can generate for example Dropdown options on REAL TIME
 *
 *  where do you put it ?
 *  i don't code how to solve this yet. but better watch out for this kind of thing
 *
 *  Oh, some advice. don't use recyclerView in this. JUST DON'T
 *  I have thinking a lot about how to abstract this into RecyclerView
 *  but it is too hard. you have to consider binding. ViewType.
 *
 *  if you think about it, why do you need recyclerview at all ?
 *  the only benefit you get from recyclerView is reducing view.
 *
 *  but all the cases that i found. you don't always get 10 views with the same input
 *  it is always at most 6 to 8 EditTextInput, 2 or 3 ImageInput. your ViewHolder isn't gonna save you from
 *  input variation
 *  
 *  that's the end of our journey. i hope this is helpful
 */